When Does Your Metabolism Slow Down? Dietitians Weigh In

When it comes to physical changes, people often wonder if their metabolism is playing a part in their body composition—especially as they age. So, we asked experts in the space to break down when metabolism slows down, what causes the metabolism to slow down, and what you can do to help it stay active. 

Registered dietitian and certified intuitive eating counselor Courtney Vickery, M.S., R.D., L.D., defines metabolism as the processes that occur in the body to create the energy used to help our body "perform even the most basic functions." Everything from breathing to maintaining homeostasis with our body temperature circles back to a healthy metabolism, and it starts, Vickery says, with the food you eat. 

"When the general population hears 'metabolism,' they are typically thinking of the three different ways we expend energy: basal metabolic rate (BMR), thermic effect of food (aka TEF—the energy required to digest, absorb, and metabolize food), and physical activity (the energy used, or calories burned, during physical activity and exercise)," Vickery explains. These are the three main components that affect a person's metabolism—i.e., the ability to use energy most optimally in the body.

According to Kyrin Dunston, M.D., FACOG, a board-certified OB/GYN with fellowship training in anti-aging, metabolic, and functional medicine, you should seek an assessment from a professional health care provider if you notice a drastic shift in your metabolism in your 20s or 30s "to prevent further complications down the line" and improve your metabolic health. This should also be a person's first course of action should they notice their metabolism has significantly sped up. Vickery warns metabolic health changes can be caused by an underlying culprit (e.g., thyroid issues) and can have "unwanted consequences on the body if left unaddressed."

Here, Vickery lists seven ways to know your metabolism is slowing down:

Another option is something called the doubly labeled water (DLW) method (almost exclusively used in research or clinical settings), which Dunston defines as another method to measure metabolism. "Here, burned calories are measured by tracking the amount of carbon dioxide that a person exhales throughout their daily activities," Dunston tells mindbodygreen. "During the test, your blood is drawn at various intervals during exercise and the levels are compared. When your body doesn't have enough oxygen to promote the conversion of calories into energy, it switches to anaerobic respiration, which produces lactic acid or lactate. This is only done in a medical setting under specific conditions," she explains.

If you come to find that your metabolism is slowing down, the great news is that our metabolism and metabolic health are flexible, with several factors under our control. Here are key lifestyle habits you can incorporate into your daily routine in order to help speed up your metabolism.

If you tend to stick to the same meals and snacks from day to day, it's time to switch up your daily menu. According to Vickery, eating a diverse diet "will ensure that you are getting the nutrients you need in order for your body to function and perform at its best." 

Vickery warns that a lack of sleep "can impact hormones that control appetite and metabolism, so getting enough sleep may help [speed things up]." If you're having trouble falling asleep or staying asleep through the night, it might be worth chatting with a sleep specialist to explore ways to improve your snooze.

In a 2016 review published in the journal Frontiers in Nutrition, researchers found that drinking water promotes water-induced thermogenesis2 (a process in which water has a thermic effect over the food you eat and therefore breaks down as energy) and increases metabolic rate by up to 30% for an hour in animal studies. By now, you probably know that staying hydrated helps you perform at your best, but according to these findings (and Vickery), it can also help your metabolism perform at its best.

"Increasing your muscle mass helps you to burn calories at a higher rate when you're sitting and doing nothing. This is because your muscles are the biggest utilizer of your caloric intake; they are hungry for energy," Dunston says. "You burn calories just sitting and breathing while doing nothing, so if you can increase your muscle mass with resistance training or weights, then you will burn more calories while sitting and doing nothing."

The formula is vegetarian and free of gluten, GMOs, dairy, and soy, and void of all major food allergens. Highlighted ingredients include veld grape (which is rich in flavonoids, stilbene, and ketosterone bioactives that combat oxidative stress, promote healthy blood pressure and fasting blood sugar, and support a healthy weight).* The supplement also delivers cayenne pepper, which is rich in antioxidants and helps curb cravings3, as well as antioxidant-rich EGCG and caffeine sourced from green tea leaves that encourage metabolic synergy4 when combined.*

Luckily, there are ways to invigorate and reset your metabolism naturally—such as making changes to your diet, getting better sleep, and taking a targeted supplement like mindbodygreen's metabolism+.* If you feel as if your metabolism might be slowing down, talk to your health care provider for further assessment.